This invention relates to an electronic musical instrument which can produce musically rich performance tones by modifying such musical tone elements or properties as the pitch, color and volume of the musical tone generated by a random signal whose content is accidentally different depending on the timing of key operation.
Generally, in an electronic musical instrument, the selection of the pitch of the generated musical tone and the designation of the timing of generating the musical tone are performed in accordance with the operation of the keys of a keyboard and the setting of the pitch standard (e.g. A.sub.4 =440Hz) of the generated musical tone and the selection of the tone color and volume thereof and of the shape of the envelope are set by various operating members (for example, a pitch setter, tone levers, etc.) mounted on a panel. Since these operating members are mounted on the panel of the musical instrument, the player cannot operate them as desired during performance so that these operating members are generally preset before performance. For this reason, musical tones having the same characters or properties (i.e., the same pitch setting, color, volume and envelope) are produced during the performance, thus resulting in monotonic performance tones of less variety.